t only the logical, but also the
historical, order of development, from the abstract and purely deductive
to the concrete and inductive. Sociology is thus the highest, most
complex, and most positive of the sciences. Herbert Spencer, condemning
this division as both incomplete and theoretically unsound, adopted a
three-fold division into (1) _abstract_ science (including logic and
mathematics) dealing with the universal forms under which all knowledge
of phenomena is possible, (2) _abstract-concrete_ science (including
mechanics, chemistry, physics), dealing with the elements of phenomena
themselves, i.e. laws of forces as deducible from the persistence of
forces, and (3) _concrete_ science (e.g. astronomy, biology, sociology),
dealing with "phenomena themselves in their totalities," the universal
laws of the continuous redistribution of Matter and Motion, Evolution
and Dissolution.

Beside the above three systems several others deserve brief mention. In
Greece at the dawn of systematic thought the physical sciences were few
in number; none the less philosophers were not agreed as to their true
relation. The Platonic school adopted a triple classification, physics,
ethics and dialectics; Aristotle's system was more complicated, nor do
we know precisely how he subdivided his three main classes, theoretical,
practical and poetical (i.e. technical, having to do with [Greek:
poiesis], creative). The second class covered ethics and politics, the
latter of which was often regarded by Aristotle as including ethics; the
third includes the useful and the imitative sciences; the first includes
metaphysics and physics. As regards pure logic Aristotle sometimes seems
to include it with metaphysics and physics, sometimes to regard it as
ancillary to all the sciences.

Thomas Hobbes (_Leviathan_) drew up an elaborate paradigm of the
sciences, the first stage of which was a dichotomy into "Naturall
Philosophy" ("consequences from the accidents of bodies naturall") and
"Politiques and Civill Philosophy" ("consequences from accidents of
Politique bodies"). The former by successive subdivisions is reduced to
eighteen special sciences; the latter is subdivided into the rights and
duties of sovereign powers, and those of the subject.

Jeremy Bentham and A.M. Ampere both drew up elaborate systems based on
the principle of dichotomy, and beginning from the distinction of mind
and body. Bentham invented an artificial terminology which is ra